Atherosclerotic disease is the leading cause of death, justifying continued effort to identify the determinants of this disease. Among the priorities for the NHLBI Division of Cardiovascular Diseases is the need to better characterize inherited predispositions to atherosclerosis in the context of understanding biological pathways of inflammation that could lead to biomarkers for prediction, early detection, and prognosis. The cellular adhesion pathway is one promising new avenue of research aligned with DCVD strategic goals. Although circulating adhesion protein levels predict increased risk of incident CHD and subsequent events in patients with acute coronary syndromes, existing literature focuses only on a small subset of proteins and genes comprising the adhesion pathway and thus few studies have assessed the combined effects of adhesion components. Therefore, we hypothesize that the adhesion pathway, as modeled by individual protein levels and a composite protein score, is associated with subclinical atherosclerosis. Furthermore, we hypothesize that variants in adhesion genes account for a significant portion of the variation in adhesion protein level and that these variants are associated with subclinical atherosclerosis. To test these hypotheses, we plan to expand phenotyping and genotyping of adhesion pathway components, incorporating results from previous genetic studies, including GWAS data, in the Multi-Ethnic Study of Atherosclerosis (MESA). Our three study aims are Aim 1) To test the hypothesis that the adhesion pathway is associated with subclinical atherosclerosis, we will analyze cross-sectional associations of 15 de novo adhesion protein levels and a composite adhesion protein score with subclinical atherosclerosis, Aim 2)To test the hypothesis that variants in adhesion genes account for a significant portion of the variation in adhesion protein level and that these variants are associated with subclinical atherosclerosis, we will assess the contribution of polymorphisms within genes directly connected to the measured protein with the corresponding circulating protein levels and we will analyze the association of these polymorphisms and longitudinal change of subclinical disease, and Aim 3) To replicate the strongest findings we will analyze the association of the most promising three proteins and 384 SNPs using 3,437 MESA subjects not included in Aims 1 & 2. Cellular adhesion is critical in the pathophysiology of atherosclerosis and a better understanding of these mechanisms on subclinical disease may have important consequences for characterizing asymptomatic individuals and for preventing and improving care of patients with atherosclerosis. Therefore, our application expands the phenotyping and genotyping of adhesion pathway components in existing stored MESA study samples to understand the relationship of adhesion on the pathogenesis of atherosclerosis. Our ability to determine the relationships among protein levels, genetic variants, and subclinical disease in substantial numbers of subjects from four ethnic groups will greatly enhance our understanding of the roles these proteins play in the pathogenesis of disease.